mirror of
https://github.com/caddyserver/caddy.git
synced 2024-12-16 21:56:40 -05:00
1414 lines
50 KiB
Go
1414 lines
50 KiB
Go
// Copyright 2015 Matthew Holt and The Caddy Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package reverseproxy
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import (
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"bytes"
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"context"
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"encoding/json"
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"errors"
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"fmt"
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"io"
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"net"
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"net/http"
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"net/http/httptrace"
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"net/netip"
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"net/textproto"
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"net/url"
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"regexp"
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"runtime"
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"strconv"
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"strings"
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"sync"
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"time"
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"github.com/caddyserver/caddy/v2"
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"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
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"github.com/caddyserver/caddy/v2/modules/caddyhttp"
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"github.com/caddyserver/caddy/v2/modules/caddyhttp/headers"
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"github.com/caddyserver/caddy/v2/modules/caddyhttp/rewrite"
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"go.uber.org/zap"
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"golang.org/x/net/http/httpguts"
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)
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var supports1xx bool
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func init() {
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// Caddy requires at least Go 1.18, but Early Hints requires Go 1.19; thus we can simply check for 1.18 in version string
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// TODO: remove this once our minimum Go version is 1.19
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supports1xx = !strings.Contains(runtime.Version(), "go1.18")
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caddy.RegisterModule(Handler{})
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}
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// Handler implements a highly configurable and production-ready reverse proxy.
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//
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// Upon proxying, this module sets the following placeholders (which can be used
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// both within and after this handler; for example, in response headers):
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//
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// Placeholder | Description
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// ------------|-------------
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// `{http.reverse_proxy.upstream.address}` | The full address to the upstream as given in the config
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// `{http.reverse_proxy.upstream.hostport}` | The host:port of the upstream
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// `{http.reverse_proxy.upstream.host}` | The host of the upstream
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// `{http.reverse_proxy.upstream.port}` | The port of the upstream
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// `{http.reverse_proxy.upstream.requests}` | The approximate current number of requests to the upstream
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// `{http.reverse_proxy.upstream.max_requests}` | The maximum approximate number of requests allowed to the upstream
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// `{http.reverse_proxy.upstream.fails}` | The number of recent failed requests to the upstream
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// `{http.reverse_proxy.upstream.latency}` | How long it took the proxy upstream to write the response header.
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// `{http.reverse_proxy.upstream.latency_ms}` | Same as 'latency', but in milliseconds.
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// `{http.reverse_proxy.upstream.duration}` | Time spent proxying to the upstream, including writing response body to client.
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// `{http.reverse_proxy.upstream.duration_ms}` | Same as 'upstream.duration', but in milliseconds.
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// `{http.reverse_proxy.duration}` | Total time spent proxying, including selecting an upstream, retries, and writing response.
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// `{http.reverse_proxy.duration_ms}` | Same as 'duration', but in milliseconds.
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type Handler struct {
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// Configures the method of transport for the proxy. A transport
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// is what performs the actual "round trip" to the backend.
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// The default transport is plaintext HTTP.
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TransportRaw json.RawMessage `json:"transport,omitempty" caddy:"namespace=http.reverse_proxy.transport inline_key=protocol"`
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// A circuit breaker may be used to relieve pressure on a backend
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// that is beginning to exhibit symptoms of stress or latency.
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// By default, there is no circuit breaker.
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CBRaw json.RawMessage `json:"circuit_breaker,omitempty" caddy:"namespace=http.reverse_proxy.circuit_breakers inline_key=type"`
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// Load balancing distributes load/requests between backends.
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LoadBalancing *LoadBalancing `json:"load_balancing,omitempty"`
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// Health checks update the status of backends, whether they are
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// up or down. Down backends will not be proxied to.
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HealthChecks *HealthChecks `json:"health_checks,omitempty"`
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// Upstreams is the static list of backends to proxy to.
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Upstreams UpstreamPool `json:"upstreams,omitempty"`
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// A module for retrieving the list of upstreams dynamically. Dynamic
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// upstreams are retrieved at every iteration of the proxy loop for
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// each request (i.e. before every proxy attempt within every request).
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// Active health checks do not work on dynamic upstreams, and passive
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// health checks are only effective on dynamic upstreams if the proxy
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// server is busy enough that concurrent requests to the same backends
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// are continuous. Instead of health checks for dynamic upstreams, it
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// is recommended that the dynamic upstream module only return available
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// backends in the first place.
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DynamicUpstreamsRaw json.RawMessage `json:"dynamic_upstreams,omitempty" caddy:"namespace=http.reverse_proxy.upstreams inline_key=source"`
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// Adjusts how often to flush the response buffer. By default,
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// no periodic flushing is done. A negative value disables
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// response buffering, and flushes immediately after each
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// write to the client. This option is ignored when the upstream's
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// response is recognized as a streaming response, or if its
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// content length is -1; for such responses, writes are flushed
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// to the client immediately.
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//
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// Normally, a request will be canceled if the client disconnects
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// before the response is received from the backend. If explicitly
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// set to -1, client disconnection will be ignored and the request
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// will be completed to help facilitate low-latency streaming.
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FlushInterval caddy.Duration `json:"flush_interval,omitempty"`
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// A list of IP ranges (supports CIDR notation) from which
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// X-Forwarded-* header values should be trusted. By default,
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// no proxies are trusted, so existing values will be ignored
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// when setting these headers. If the proxy is trusted, then
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// existing values will be used when constructing the final
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// header values.
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TrustedProxies []string `json:"trusted_proxies,omitempty"`
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// Headers manipulates headers between Caddy and the backend.
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// By default, all headers are passed-thru without changes,
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// with the exceptions of special hop-by-hop headers.
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//
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// X-Forwarded-For, X-Forwarded-Proto and X-Forwarded-Host
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// are also set implicitly.
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Headers *headers.Handler `json:"headers,omitempty"`
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// If true, the entire request body will be read and buffered
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// in memory before being proxied to the backend. This should
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// be avoided if at all possible for performance reasons, but
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// could be useful if the backend is intolerant of read latency.
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BufferRequests bool `json:"buffer_requests,omitempty"`
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// If true, the entire response body will be read and buffered
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// in memory before being proxied to the client. This should
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// be avoided if at all possible for performance reasons, but
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// could be useful if the backend has tighter memory constraints.
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BufferResponses bool `json:"buffer_responses,omitempty"`
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// If body buffering is enabled, the maximum size of the buffers
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// used for the requests and responses (in bytes).
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MaxBufferSize int64 `json:"max_buffer_size,omitempty"`
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// If configured, rewrites the copy of the upstream request.
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// Allows changing the request method and URI (path and query).
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// Since the rewrite is applied to the copy, it does not persist
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// past the reverse proxy handler.
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// If the method is changed to `GET` or `HEAD`, the request body
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// will not be copied to the backend. This allows a later request
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// handler -- either in a `handle_response` route, or after -- to
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// read the body.
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// By default, no rewrite is performed, and the method and URI
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// from the incoming request is used as-is for proxying.
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Rewrite *rewrite.Rewrite `json:"rewrite,omitempty"`
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// List of handlers and their associated matchers to evaluate
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// after successful roundtrips. The first handler that matches
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// the response from a backend will be invoked. The response
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// body from the backend will not be written to the client;
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// it is up to the handler to finish handling the response.
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// If passive health checks are enabled, any errors from the
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// handler chain will not affect the health status of the
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// backend.
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//
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// Three new placeholders are available in this handler chain:
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// - `{http.reverse_proxy.status_code}` The status code from the response
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// - `{http.reverse_proxy.status_text}` The status text from the response
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// - `{http.reverse_proxy.header.*}` The headers from the response
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HandleResponse []caddyhttp.ResponseHandler `json:"handle_response,omitempty"`
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Transport http.RoundTripper `json:"-"`
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CB CircuitBreaker `json:"-"`
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DynamicUpstreams UpstreamSource `json:"-"`
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// Holds the parsed CIDR ranges from TrustedProxies
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trustedProxies []netip.Prefix
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// Holds the named response matchers from the Caddyfile while adapting
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responseMatchers map[string]caddyhttp.ResponseMatcher
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// Holds the handle_response Caddyfile tokens while adapting
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handleResponseSegments []*caddyfile.Dispenser
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ctx caddy.Context
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logger *zap.Logger
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}
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// CaddyModule returns the Caddy module information.
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func (Handler) CaddyModule() caddy.ModuleInfo {
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return caddy.ModuleInfo{
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ID: "http.handlers.reverse_proxy",
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New: func() caddy.Module { return new(Handler) },
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}
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}
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// Provision ensures that h is set up properly before use.
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func (h *Handler) Provision(ctx caddy.Context) error {
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h.ctx = ctx
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h.logger = ctx.Logger(h)
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// verify SRV compatibility - TODO: LookupSRV deprecated; will be removed
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for i, v := range h.Upstreams {
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if v.LookupSRV == "" {
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continue
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}
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if h.HealthChecks != nil && h.HealthChecks.Active != nil {
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return fmt.Errorf(`upstream: lookup_srv is incompatible with active health checks: %d: {"dial": %q, "lookup_srv": %q}`, i, v.Dial, v.LookupSRV)
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}
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if v.Dial != "" {
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return fmt.Errorf(`upstream: specifying dial address is incompatible with lookup_srv: %d: {"dial": %q, "lookup_srv": %q}`, i, v.Dial, v.LookupSRV)
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}
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}
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// start by loading modules
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if h.TransportRaw != nil {
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mod, err := ctx.LoadModule(h, "TransportRaw")
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if err != nil {
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return fmt.Errorf("loading transport: %v", err)
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}
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h.Transport = mod.(http.RoundTripper)
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}
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if h.LoadBalancing != nil && h.LoadBalancing.SelectionPolicyRaw != nil {
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mod, err := ctx.LoadModule(h.LoadBalancing, "SelectionPolicyRaw")
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if err != nil {
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return fmt.Errorf("loading load balancing selection policy: %s", err)
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}
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h.LoadBalancing.SelectionPolicy = mod.(Selector)
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}
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if h.CBRaw != nil {
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mod, err := ctx.LoadModule(h, "CBRaw")
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if err != nil {
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return fmt.Errorf("loading circuit breaker: %s", err)
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}
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h.CB = mod.(CircuitBreaker)
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}
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if h.DynamicUpstreamsRaw != nil {
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mod, err := ctx.LoadModule(h, "DynamicUpstreamsRaw")
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if err != nil {
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return fmt.Errorf("loading upstream source module: %v", err)
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}
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h.DynamicUpstreams = mod.(UpstreamSource)
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}
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// parse trusted proxy CIDRs ahead of time
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for _, str := range h.TrustedProxies {
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if strings.Contains(str, "/") {
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ipNet, err := netip.ParsePrefix(str)
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if err != nil {
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return fmt.Errorf("parsing CIDR expression: '%s': %v", str, err)
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}
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h.trustedProxies = append(h.trustedProxies, ipNet)
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} else {
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ipAddr, err := netip.ParseAddr(str)
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if err != nil {
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return fmt.Errorf("invalid IP address: '%s': %v", str, err)
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}
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ipNew := netip.PrefixFrom(ipAddr, ipAddr.BitLen())
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h.trustedProxies = append(h.trustedProxies, ipNew)
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}
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}
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// ensure any embedded headers handler module gets provisioned
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// (see https://caddy.community/t/set-cookie-manipulation-in-reverse-proxy/7666?u=matt
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// for what happens if we forget to provision it)
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if h.Headers != nil {
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err := h.Headers.Provision(ctx)
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if err != nil {
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return fmt.Errorf("provisioning embedded headers handler: %v", err)
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}
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}
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if h.Rewrite != nil {
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err := h.Rewrite.Provision(ctx)
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if err != nil {
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return fmt.Errorf("provisioning rewrite: %v", err)
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}
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}
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// set up transport
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if h.Transport == nil {
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t := &HTTPTransport{}
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err := t.Provision(ctx)
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if err != nil {
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return fmt.Errorf("provisioning default transport: %v", err)
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}
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h.Transport = t
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}
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// set up load balancing
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if h.LoadBalancing == nil {
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h.LoadBalancing = new(LoadBalancing)
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}
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if h.LoadBalancing.SelectionPolicy == nil {
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h.LoadBalancing.SelectionPolicy = RandomSelection{}
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}
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if h.LoadBalancing.TryDuration > 0 && h.LoadBalancing.TryInterval == 0 {
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// a non-zero try_duration with a zero try_interval
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// will always spin the CPU for try_duration if the
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// upstream is local or low-latency; avoid that by
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// defaulting to a sane wait period between attempts
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h.LoadBalancing.TryInterval = caddy.Duration(250 * time.Millisecond)
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}
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lbMatcherSets, err := ctx.LoadModule(h.LoadBalancing, "RetryMatchRaw")
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if err != nil {
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return err
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}
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err = h.LoadBalancing.RetryMatch.FromInterface(lbMatcherSets)
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if err != nil {
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return err
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}
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// set up upstreams
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for _, u := range h.Upstreams {
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h.provisionUpstream(u)
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}
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if h.HealthChecks != nil {
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// set defaults on passive health checks, if necessary
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if h.HealthChecks.Passive != nil {
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if h.HealthChecks.Passive.FailDuration > 0 && h.HealthChecks.Passive.MaxFails == 0 {
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h.HealthChecks.Passive.MaxFails = 1
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}
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}
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// if active health checks are enabled, configure them and start a worker
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if h.HealthChecks.Active != nil && (h.HealthChecks.Active.Path != "" ||
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h.HealthChecks.Active.URI != "" ||
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h.HealthChecks.Active.Port != 0) {
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h.HealthChecks.Active.logger = h.logger.Named("health_checker.active")
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timeout := time.Duration(h.HealthChecks.Active.Timeout)
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if timeout == 0 {
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timeout = 5 * time.Second
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}
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if h.HealthChecks.Active.Path != "" {
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h.HealthChecks.Active.logger.Warn("the 'path' option is deprecated, please use 'uri' instead!")
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}
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// parse the URI string (supports path and query)
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if h.HealthChecks.Active.URI != "" {
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parsedURI, err := url.Parse(h.HealthChecks.Active.URI)
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if err != nil {
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return err
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}
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h.HealthChecks.Active.uri = parsedURI
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}
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h.HealthChecks.Active.httpClient = &http.Client{
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Timeout: timeout,
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Transport: h.Transport,
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}
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for _, upstream := range h.Upstreams {
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// if there's an alternative port for health-check provided in the config,
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// then use it, otherwise use the port of upstream.
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if h.HealthChecks.Active.Port != 0 {
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upstream.activeHealthCheckPort = h.HealthChecks.Active.Port
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}
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}
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if h.HealthChecks.Active.Interval == 0 {
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h.HealthChecks.Active.Interval = caddy.Duration(30 * time.Second)
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}
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if h.HealthChecks.Active.ExpectBody != "" {
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var err error
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h.HealthChecks.Active.bodyRegexp, err = regexp.Compile(h.HealthChecks.Active.ExpectBody)
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if err != nil {
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return fmt.Errorf("expect_body: compiling regular expression: %v", err)
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}
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}
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go h.activeHealthChecker()
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}
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}
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// set up any response routes
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for i, rh := range h.HandleResponse {
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err := rh.Provision(ctx)
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if err != nil {
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return fmt.Errorf("provisioning response handler %d: %v", i, err)
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}
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}
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upstreamHealthyUpdater := newMetricsUpstreamsHealthyUpdater(h)
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upstreamHealthyUpdater.Init()
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return nil
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}
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// Cleanup cleans up the resources made by h during provisioning.
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func (h *Handler) Cleanup() error {
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// TODO: Close keepalive connections on reload? https://github.com/caddyserver/caddy/pull/2507/files#diff-70219fd88fe3f36834f474ce6537ed26R762
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// remove hosts from our config from the pool
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for _, upstream := range h.Upstreams {
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_, _ = hosts.Delete(upstream.String())
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}
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return nil
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}
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func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
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repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)
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// prepare the request for proxying; this is needed only once
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clonedReq, err := h.prepareRequest(r, repl)
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if err != nil {
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return caddyhttp.Error(http.StatusInternalServerError,
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fmt.Errorf("preparing request for upstream round-trip: %v", err))
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}
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// we will need the original headers and Host value if
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// header operations are configured; this is so that each
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// retry can apply the modifications, because placeholders
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// may be used which depend on the selected upstream for
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// their values
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reqHost := clonedReq.Host
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reqHeader := clonedReq.Header
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start := time.Now()
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defer func() {
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// total proxying duration, including time spent on LB and retries
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repl.Set("http.reverse_proxy.duration", time.Since(start))
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repl.Set("http.reverse_proxy.duration_ms", time.Since(start).Seconds()*1e3) // multiply seconds to preserve decimal (see #4666)
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}()
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// in the proxy loop, each iteration is an attempt to proxy the request,
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// and because we may retry some number of times, carry over the error
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// from previous tries because of the nuances of load balancing & retries
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var proxyErr error
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var retries int
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for {
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var done bool
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done, proxyErr = h.proxyLoopIteration(clonedReq, r, w, proxyErr, start, retries, repl, reqHeader, reqHost, next)
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if done {
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break
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}
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retries++
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}
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if proxyErr != nil {
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return statusError(proxyErr)
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}
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return nil
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}
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// proxyLoopIteration implements an iteration of the proxy loop. Despite the enormous amount of local state
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// that has to be passed in, we brought this into its own method so that we could run defer more easily.
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// It returns true when the loop is done and should break; false otherwise. The error value returned should
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// be assigned to the proxyErr value for the next iteration of the loop (or the error handled after break).
|
|
func (h *Handler) proxyLoopIteration(r *http.Request, origReq *http.Request, w http.ResponseWriter, proxyErr error, start time.Time, retries int,
|
|
repl *caddy.Replacer, reqHeader http.Header, reqHost string, next caddyhttp.Handler) (bool, error) {
|
|
// get the updated list of upstreams
|
|
upstreams := h.Upstreams
|
|
if h.DynamicUpstreams != nil {
|
|
dUpstreams, err := h.DynamicUpstreams.GetUpstreams(r)
|
|
if err != nil {
|
|
h.logger.Error("failed getting dynamic upstreams; falling back to static upstreams", zap.Error(err))
|
|
} else {
|
|
upstreams = dUpstreams
|
|
for _, dUp := range dUpstreams {
|
|
h.provisionUpstream(dUp)
|
|
}
|
|
h.logger.Debug("provisioned dynamic upstreams", zap.Int("count", len(dUpstreams)))
|
|
defer func() {
|
|
// these upstreams are dynamic, so they are only used for this iteration
|
|
// of the proxy loop; be sure to let them go away when we're done with them
|
|
for _, upstream := range dUpstreams {
|
|
_, _ = hosts.Delete(upstream.String())
|
|
}
|
|
}()
|
|
}
|
|
}
|
|
|
|
// choose an available upstream
|
|
upstream := h.LoadBalancing.SelectionPolicy.Select(upstreams, r, w)
|
|
if upstream == nil {
|
|
if proxyErr == nil {
|
|
proxyErr = caddyhttp.Error(http.StatusServiceUnavailable, fmt.Errorf("no upstreams available"))
|
|
}
|
|
if !h.LoadBalancing.tryAgain(h.ctx, start, retries, proxyErr, r) {
|
|
return true, proxyErr
|
|
}
|
|
return false, proxyErr
|
|
}
|
|
|
|
// the dial address may vary per-request if placeholders are
|
|
// used, so perform those replacements here; the resulting
|
|
// DialInfo struct should have valid network address syntax
|
|
dialInfo, err := upstream.fillDialInfo(r)
|
|
if err != nil {
|
|
return true, fmt.Errorf("making dial info: %v", err)
|
|
}
|
|
|
|
h.logger.Debug("selected upstream",
|
|
zap.String("dial", dialInfo.Address),
|
|
zap.Int("total_upstreams", len(upstreams)))
|
|
|
|
// attach to the request information about how to dial the upstream;
|
|
// this is necessary because the information cannot be sufficiently
|
|
// or satisfactorily represented in a URL
|
|
caddyhttp.SetVar(r.Context(), dialInfoVarKey, dialInfo)
|
|
|
|
// set placeholders with information about this upstream
|
|
repl.Set("http.reverse_proxy.upstream.address", dialInfo.String())
|
|
repl.Set("http.reverse_proxy.upstream.hostport", dialInfo.Address)
|
|
repl.Set("http.reverse_proxy.upstream.host", dialInfo.Host)
|
|
repl.Set("http.reverse_proxy.upstream.port", dialInfo.Port)
|
|
repl.Set("http.reverse_proxy.upstream.requests", upstream.Host.NumRequests())
|
|
repl.Set("http.reverse_proxy.upstream.max_requests", upstream.MaxRequests)
|
|
repl.Set("http.reverse_proxy.upstream.fails", upstream.Host.Fails())
|
|
|
|
// mutate request headers according to this upstream;
|
|
// because we're in a retry loop, we have to copy
|
|
// headers (and the r.Host value) from the original
|
|
// so that each retry is identical to the first
|
|
if h.Headers != nil && h.Headers.Request != nil {
|
|
r.Header = make(http.Header)
|
|
copyHeader(r.Header, reqHeader)
|
|
r.Host = reqHost
|
|
h.Headers.Request.ApplyToRequest(r)
|
|
}
|
|
|
|
// proxy the request to that upstream
|
|
proxyErr = h.reverseProxy(w, r, origReq, repl, dialInfo, next)
|
|
if proxyErr == nil || errors.Is(proxyErr, context.Canceled) {
|
|
// context.Canceled happens when the downstream client
|
|
// cancels the request, which is not our failure
|
|
return true, nil
|
|
}
|
|
|
|
// if the roundtrip was successful, don't retry the request or
|
|
// ding the health status of the upstream (an error can still
|
|
// occur after the roundtrip if, for example, a response handler
|
|
// after the roundtrip returns an error)
|
|
if succ, ok := proxyErr.(roundtripSucceeded); ok {
|
|
return true, succ.error
|
|
}
|
|
|
|
// remember this failure (if enabled)
|
|
h.countFailure(upstream)
|
|
|
|
// if we've tried long enough, break
|
|
if !h.LoadBalancing.tryAgain(h.ctx, start, retries, proxyErr, r) {
|
|
return true, proxyErr
|
|
}
|
|
|
|
return false, proxyErr
|
|
}
|
|
|
|
// prepareRequest clones req so that it can be safely modified without
|
|
// changing the original request or introducing data races. It then
|
|
// modifies it so that it is ready to be proxied, except for directing
|
|
// to a specific upstream. This method adjusts headers and other relevant
|
|
// properties of the cloned request and should be done just once (before
|
|
// proxying) regardless of proxy retries. This assumes that no mutations
|
|
// of the cloned request are performed by h during or after proxying.
|
|
func (h Handler) prepareRequest(req *http.Request, repl *caddy.Replacer) (*http.Request, error) {
|
|
req = cloneRequest(req)
|
|
|
|
// if enabled, perform rewrites on the cloned request; if
|
|
// the method is GET or HEAD, prevent the request body
|
|
// from being copied to the upstream
|
|
if h.Rewrite != nil {
|
|
changed := h.Rewrite.Rewrite(req, repl)
|
|
if changed && (h.Rewrite.Method == "GET" || h.Rewrite.Method == "HEAD") {
|
|
req.ContentLength = 0
|
|
req.Body = nil
|
|
}
|
|
}
|
|
|
|
// if enabled, buffer client request; this should only be
|
|
// enabled if the upstream requires it and does not work
|
|
// with "slow clients" (gunicorn, etc.) - this obviously
|
|
// has a perf overhead and makes the proxy at risk of
|
|
// exhausting memory and more susceptible to slowloris
|
|
// attacks, so it is strongly recommended to only use this
|
|
// feature if absolutely required, if read timeouts are
|
|
// set, and if body size is limited
|
|
if h.BufferRequests && req.Body != nil {
|
|
req.Body = h.bufferedBody(req.Body)
|
|
}
|
|
|
|
if req.ContentLength == 0 {
|
|
req.Body = nil // Issue golang/go#16036: nil Body for http.Transport retries
|
|
}
|
|
|
|
req.Close = false
|
|
|
|
// if User-Agent is not set by client, then explicitly
|
|
// disable it so it's not set to default value by std lib
|
|
if _, ok := req.Header["User-Agent"]; !ok {
|
|
req.Header.Set("User-Agent", "")
|
|
}
|
|
|
|
reqUpType := upgradeType(req.Header)
|
|
removeConnectionHeaders(req.Header)
|
|
|
|
// Remove hop-by-hop headers to the backend. Especially
|
|
// important is "Connection" because we want a persistent
|
|
// connection, regardless of what the client sent to us.
|
|
// Issue golang/go#46313: don't skip if field is empty.
|
|
for _, h := range hopHeaders {
|
|
// Issue golang/go#21096: tell backend applications that care about trailer support
|
|
// that we support trailers. (We do, but we don't go out of our way to
|
|
// advertise that unless the incoming client request thought it was worth
|
|
// mentioning.)
|
|
if h == "Te" && httpguts.HeaderValuesContainsToken(req.Header["Te"], "trailers") {
|
|
req.Header.Set("Te", "trailers")
|
|
continue
|
|
}
|
|
req.Header.Del(h)
|
|
}
|
|
|
|
// After stripping all the hop-by-hop connection headers above, add back any
|
|
// necessary for protocol upgrades, such as for websockets.
|
|
if reqUpType != "" {
|
|
req.Header.Set("Connection", "Upgrade")
|
|
req.Header.Set("Upgrade", reqUpType)
|
|
}
|
|
|
|
// Add the supported X-Forwarded-* headers
|
|
err := h.addForwardedHeaders(req)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return req, nil
|
|
}
|
|
|
|
// addForwardedHeaders adds the de-facto standard X-Forwarded-*
|
|
// headers to the request before it is sent upstream.
|
|
//
|
|
// These headers are security sensitive, so care is taken to only
|
|
// use existing values for these headers from the incoming request
|
|
// if the client IP is trusted (i.e. coming from a trusted proxy
|
|
// sitting in front of this server). If the request didn't have
|
|
// the headers at all, then they will be added with the values
|
|
// that we can glean from the request.
|
|
func (h Handler) addForwardedHeaders(req *http.Request) error {
|
|
// Parse the remote IP, ignore the error as non-fatal,
|
|
// but the remote IP is required to continue, so we
|
|
// just return early. This should probably never happen
|
|
// though, unless some other module manipulated the request's
|
|
// remote address and used an invalid value.
|
|
clientIP, _, err := net.SplitHostPort(req.RemoteAddr)
|
|
if err != nil {
|
|
// Remove the `X-Forwarded-*` headers to avoid upstreams
|
|
// potentially trusting a header that came from the client
|
|
req.Header.Del("X-Forwarded-For")
|
|
req.Header.Del("X-Forwarded-Proto")
|
|
req.Header.Del("X-Forwarded-Host")
|
|
return nil
|
|
}
|
|
|
|
// Client IP may contain a zone if IPv6, so we need
|
|
// to pull that out before parsing the IP
|
|
if before, _, found := strings.Cut(clientIP, "%"); found {
|
|
clientIP = before
|
|
}
|
|
ipAddr, err := netip.ParseAddr(clientIP)
|
|
if err != nil {
|
|
return fmt.Errorf("invalid IP address: '%s': %v", clientIP, err)
|
|
}
|
|
|
|
// Check if the client is a trusted proxy
|
|
trusted := false
|
|
for _, ipRange := range h.trustedProxies {
|
|
if ipRange.Contains(ipAddr) {
|
|
trusted = true
|
|
break
|
|
}
|
|
}
|
|
|
|
// If we aren't the first proxy, and the proxy is trusted,
|
|
// retain prior X-Forwarded-For information as a comma+space
|
|
// separated list and fold multiple headers into one.
|
|
clientXFF := clientIP
|
|
prior, ok, omit := allHeaderValues(req.Header, "X-Forwarded-For")
|
|
if trusted && ok && prior != "" {
|
|
clientXFF = prior + ", " + clientXFF
|
|
}
|
|
if !omit {
|
|
req.Header.Set("X-Forwarded-For", clientXFF)
|
|
}
|
|
|
|
// Set X-Forwarded-Proto; many backend apps expect this,
|
|
// so that they can properly craft URLs with the right
|
|
// scheme to match the original request
|
|
proto := "https"
|
|
if req.TLS == nil {
|
|
proto = "http"
|
|
}
|
|
prior, ok, omit = lastHeaderValue(req.Header, "X-Forwarded-Proto")
|
|
if trusted && ok && prior != "" {
|
|
proto = prior
|
|
}
|
|
if !omit {
|
|
req.Header.Set("X-Forwarded-Proto", proto)
|
|
}
|
|
|
|
// Set X-Forwarded-Host; often this is redundant because
|
|
// we pass through the request Host as-is, but in situations
|
|
// where we proxy over HTTPS, the user may need to override
|
|
// Host themselves, so it's helpful to send the original too.
|
|
host := req.Host
|
|
prior, ok, omit = lastHeaderValue(req.Header, "X-Forwarded-Host")
|
|
if trusted && ok && prior != "" {
|
|
host = prior
|
|
}
|
|
if !omit {
|
|
req.Header.Set("X-Forwarded-Host", host)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// reverseProxy performs a round-trip to the given backend and processes the response with the client.
|
|
// (This method is mostly the beginning of what was borrowed from the net/http/httputil package in the
|
|
// Go standard library which was used as the foundation.)
|
|
func (h *Handler) reverseProxy(rw http.ResponseWriter, req *http.Request, origReq *http.Request, repl *caddy.Replacer, di DialInfo, next caddyhttp.Handler) error {
|
|
_ = di.Upstream.Host.countRequest(1)
|
|
//nolint:errcheck
|
|
defer di.Upstream.Host.countRequest(-1)
|
|
|
|
// point the request to this upstream
|
|
h.directRequest(req, di)
|
|
|
|
server := req.Context().Value(caddyhttp.ServerCtxKey).(*caddyhttp.Server)
|
|
shouldLogCredentials := server.Logs != nil && server.Logs.ShouldLogCredentials
|
|
|
|
if supports1xx {
|
|
// Forward 1xx status codes, backported from https://github.com/golang/go/pull/53164
|
|
trace := &httptrace.ClientTrace{
|
|
Got1xxResponse: func(code int, header textproto.MIMEHeader) error {
|
|
h := rw.Header()
|
|
copyHeader(h, http.Header(header))
|
|
rw.WriteHeader(code)
|
|
|
|
// Clear headers, it's not automatically done by ResponseWriter.WriteHeader() for 1xx responses
|
|
for k := range h {
|
|
delete(h, k)
|
|
}
|
|
|
|
return nil
|
|
},
|
|
}
|
|
req = req.WithContext(httptrace.WithClientTrace(req.Context(), trace))
|
|
}
|
|
|
|
// if FlushInterval is explicitly configured to -1 (i.e. flush continuously to achieve
|
|
// low-latency streaming), don't let the transport cancel the request if the client
|
|
// disconnects: user probably wants us to finish sending the data to the upstream
|
|
// regardless, and we should expect client disconnection in low-latency streaming
|
|
// scenarios (see issue #4922)
|
|
if h.FlushInterval == -1 {
|
|
req = req.WithContext(ignoreClientGoneContext{req.Context(), h.ctx.Done()})
|
|
}
|
|
|
|
// do the round-trip; emit debug log with values we know are
|
|
// safe, or if there is no error, emit fuller log entry
|
|
start := time.Now()
|
|
res, err := h.Transport.RoundTrip(req)
|
|
duration := time.Since(start)
|
|
logger := h.logger.With(
|
|
zap.String("upstream", di.Upstream.String()),
|
|
zap.Duration("duration", duration),
|
|
zap.Object("request", caddyhttp.LoggableHTTPRequest{
|
|
Request: req,
|
|
ShouldLogCredentials: shouldLogCredentials,
|
|
}),
|
|
)
|
|
if err != nil {
|
|
logger.Debug("upstream roundtrip", zap.Error(err))
|
|
return err
|
|
}
|
|
logger.Debug("upstream roundtrip",
|
|
zap.Object("headers", caddyhttp.LoggableHTTPHeader{
|
|
Header: res.Header,
|
|
ShouldLogCredentials: shouldLogCredentials,
|
|
}),
|
|
zap.Int("status", res.StatusCode))
|
|
|
|
// duration until upstream wrote response headers (roundtrip duration)
|
|
repl.Set("http.reverse_proxy.upstream.latency", duration)
|
|
repl.Set("http.reverse_proxy.upstream.latency_ms", duration.Seconds()*1e3) // multiply seconds to preserve decimal (see #4666)
|
|
|
|
// update circuit breaker on current conditions
|
|
if di.Upstream.cb != nil {
|
|
di.Upstream.cb.RecordMetric(res.StatusCode, duration)
|
|
}
|
|
|
|
// perform passive health checks (if enabled)
|
|
if h.HealthChecks != nil && h.HealthChecks.Passive != nil {
|
|
// strike if the status code matches one that is "bad"
|
|
for _, badStatus := range h.HealthChecks.Passive.UnhealthyStatus {
|
|
if caddyhttp.StatusCodeMatches(res.StatusCode, badStatus) {
|
|
h.countFailure(di.Upstream)
|
|
}
|
|
}
|
|
|
|
// strike if the roundtrip took too long
|
|
if h.HealthChecks.Passive.UnhealthyLatency > 0 &&
|
|
duration >= time.Duration(h.HealthChecks.Passive.UnhealthyLatency) {
|
|
h.countFailure(di.Upstream)
|
|
}
|
|
}
|
|
|
|
// if enabled, buffer the response body
|
|
if h.BufferResponses {
|
|
res.Body = h.bufferedBody(res.Body)
|
|
}
|
|
|
|
// see if any response handler is configured for this response from the backend
|
|
for i, rh := range h.HandleResponse {
|
|
if rh.Match != nil && !rh.Match.Match(res.StatusCode, res.Header) {
|
|
continue
|
|
}
|
|
|
|
// if configured to only change the status code,
|
|
// do that then continue regular proxy response
|
|
if statusCodeStr := rh.StatusCode.String(); statusCodeStr != "" {
|
|
statusCode, err := strconv.Atoi(repl.ReplaceAll(statusCodeStr, ""))
|
|
if err != nil {
|
|
return caddyhttp.Error(http.StatusInternalServerError, err)
|
|
}
|
|
if statusCode != 0 {
|
|
res.StatusCode = statusCode
|
|
}
|
|
break
|
|
}
|
|
|
|
// otherwise, if there are any routes configured, execute those as the
|
|
// actual response instead of what we got from the proxy backend
|
|
if len(rh.Routes) == 0 {
|
|
continue
|
|
}
|
|
|
|
// set up the replacer so that parts of the original response can be
|
|
// used for routing decisions
|
|
for field, value := range res.Header {
|
|
repl.Set("http.reverse_proxy.header."+field, strings.Join(value, ","))
|
|
}
|
|
repl.Set("http.reverse_proxy.status_code", res.StatusCode)
|
|
repl.Set("http.reverse_proxy.status_text", res.Status)
|
|
|
|
h.logger.Debug("handling response", zap.Int("handler", i))
|
|
|
|
// we make some data available via request context to child routes
|
|
// so that they may inherit some options and functions from the
|
|
// handler, and be able to copy the response.
|
|
// we use the original request here, so that any routes from 'next'
|
|
// see the original request rather than the proxy cloned request.
|
|
hrc := &handleResponseContext{
|
|
handler: h,
|
|
response: res,
|
|
start: start,
|
|
logger: logger,
|
|
}
|
|
ctx := origReq.Context()
|
|
ctx = context.WithValue(ctx, proxyHandleResponseContextCtxKey, hrc)
|
|
|
|
// pass the request through the response handler routes
|
|
routeErr := rh.Routes.Compile(next).ServeHTTP(rw, origReq.WithContext(ctx))
|
|
|
|
// close the response body afterwards, since we don't need it anymore;
|
|
// either a route had 'copy_response' which already consumed the body,
|
|
// or some other terminal handler ran which doesn't need the response
|
|
// body after that point (e.g. 'file_server' for X-Accel-Redirect flow),
|
|
// or we fell through to subsequent handlers past this proxy
|
|
// (e.g. forward auth's 2xx response flow).
|
|
if !hrc.isFinalized {
|
|
res.Body.Close()
|
|
}
|
|
|
|
// wrap any route error in roundtripSucceeded so caller knows that
|
|
// the roundtrip was successful and to not retry
|
|
if routeErr != nil {
|
|
return roundtripSucceeded{routeErr}
|
|
}
|
|
|
|
// we're done handling the response, and we don't want to
|
|
// fall through to the default finalize/copy behaviour
|
|
return nil
|
|
}
|
|
|
|
// copy the response body and headers back to the upstream client
|
|
return h.finalizeResponse(rw, req, res, repl, start, logger)
|
|
}
|
|
|
|
// finalizeResponse prepares and copies the response.
|
|
func (h Handler) finalizeResponse(
|
|
rw http.ResponseWriter,
|
|
req *http.Request,
|
|
res *http.Response,
|
|
repl *caddy.Replacer,
|
|
start time.Time,
|
|
logger *zap.Logger,
|
|
) error {
|
|
// deal with 101 Switching Protocols responses: (WebSocket, h2c, etc)
|
|
if res.StatusCode == http.StatusSwitchingProtocols {
|
|
h.handleUpgradeResponse(logger, rw, req, res)
|
|
return nil
|
|
}
|
|
|
|
removeConnectionHeaders(res.Header)
|
|
|
|
for _, h := range hopHeaders {
|
|
res.Header.Del(h)
|
|
}
|
|
|
|
// apply any response header operations
|
|
if h.Headers != nil && h.Headers.Response != nil {
|
|
if h.Headers.Response.Require == nil ||
|
|
h.Headers.Response.Require.Match(res.StatusCode, res.Header) {
|
|
h.Headers.Response.ApplyTo(res.Header, repl)
|
|
}
|
|
}
|
|
|
|
copyHeader(rw.Header(), res.Header)
|
|
|
|
// The "Trailer" header isn't included in the Transport's response,
|
|
// at least for *http.Transport. Build it up from Trailer.
|
|
announcedTrailers := len(res.Trailer)
|
|
if announcedTrailers > 0 {
|
|
trailerKeys := make([]string, 0, len(res.Trailer))
|
|
for k := range res.Trailer {
|
|
trailerKeys = append(trailerKeys, k)
|
|
}
|
|
rw.Header().Add("Trailer", strings.Join(trailerKeys, ", "))
|
|
}
|
|
|
|
rw.WriteHeader(res.StatusCode)
|
|
|
|
err := h.copyResponse(rw, res.Body, h.flushInterval(req, res))
|
|
res.Body.Close() // close now, instead of defer, to populate res.Trailer
|
|
if err != nil {
|
|
// we're streaming the response and we've already written headers, so
|
|
// there's nothing an error handler can do to recover at this point;
|
|
// the standard lib's proxy panics at this point, but we'll just log
|
|
// the error and abort the stream here
|
|
h.logger.Error("aborting with incomplete response", zap.Error(err))
|
|
return nil
|
|
}
|
|
|
|
if len(res.Trailer) > 0 {
|
|
// Force chunking if we saw a response trailer.
|
|
// This prevents net/http from calculating the length for short
|
|
// bodies and adding a Content-Length.
|
|
if fl, ok := rw.(http.Flusher); ok {
|
|
fl.Flush()
|
|
}
|
|
}
|
|
|
|
// total duration spent proxying, including writing response body
|
|
repl.Set("http.reverse_proxy.upstream.duration", time.Since(start))
|
|
repl.Set("http.reverse_proxy.upstream.duration_ms", time.Since(start).Seconds()*1e3)
|
|
|
|
if len(res.Trailer) == announcedTrailers {
|
|
copyHeader(rw.Header(), res.Trailer)
|
|
return nil
|
|
}
|
|
|
|
for k, vv := range res.Trailer {
|
|
k = http.TrailerPrefix + k
|
|
for _, v := range vv {
|
|
rw.Header().Add(k, v)
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// tryAgain takes the time that the handler was initially invoked,
|
|
// the amount of retries already performed, as well as any error
|
|
// currently obtained, and the request being tried, and returns
|
|
// true if another attempt should be made at proxying the request.
|
|
// If true is returned, it has already blocked long enough before
|
|
// the next retry (i.e. no more sleeping is needed). If false is
|
|
// returned, the handler should stop trying to proxy the request.
|
|
func (lb LoadBalancing) tryAgain(ctx caddy.Context, start time.Time, retries int, proxyErr error, req *http.Request) bool {
|
|
// no retries are configured
|
|
if lb.TryDuration == 0 && lb.Retries == 0 {
|
|
return false
|
|
}
|
|
|
|
// if we've tried long enough, break
|
|
if lb.TryDuration > 0 && time.Since(start) >= time.Duration(lb.TryDuration) {
|
|
return false
|
|
}
|
|
|
|
// if we've reached the retry limit, break
|
|
if lb.Retries > 0 && retries >= lb.Retries {
|
|
return false
|
|
}
|
|
|
|
// if the error occurred while dialing (i.e. a connection
|
|
// could not even be established to the upstream), then it
|
|
// should be safe to retry, since without a connection, no
|
|
// HTTP request can be transmitted; but if the error is not
|
|
// specifically a dialer error, we need to be careful
|
|
if _, ok := proxyErr.(DialError); proxyErr != nil && !ok {
|
|
// if the error occurred after a connection was established,
|
|
// we have to assume the upstream received the request, and
|
|
// retries need to be carefully decided, because some requests
|
|
// are not idempotent
|
|
if lb.RetryMatch == nil && req.Method != "GET" {
|
|
// by default, don't retry requests if they aren't GET
|
|
return false
|
|
}
|
|
if !lb.RetryMatch.AnyMatch(req) {
|
|
return false
|
|
}
|
|
}
|
|
|
|
// fast path; if the interval is zero, we don't need to wait
|
|
if lb.TryInterval == 0 {
|
|
return true
|
|
}
|
|
|
|
// otherwise, wait and try the next available host
|
|
timer := time.NewTimer(time.Duration(lb.TryInterval))
|
|
select {
|
|
case <-timer.C:
|
|
return true
|
|
case <-ctx.Done():
|
|
if !timer.Stop() {
|
|
// if the timer has been stopped then read from the channel
|
|
<-timer.C
|
|
}
|
|
return false
|
|
}
|
|
}
|
|
|
|
// directRequest modifies only req.URL so that it points to the upstream
|
|
// in the given DialInfo. It must modify ONLY the request URL.
|
|
func (Handler) directRequest(req *http.Request, di DialInfo) {
|
|
// we need a host, so set the upstream's host address
|
|
reqHost := di.Address
|
|
|
|
// if the port equates to the scheme, strip the port because
|
|
// it's weird to make a request like http://example.com:80/.
|
|
if (req.URL.Scheme == "http" && di.Port == "80") ||
|
|
(req.URL.Scheme == "https" && di.Port == "443") {
|
|
reqHost = di.Host
|
|
}
|
|
|
|
req.URL.Host = reqHost
|
|
}
|
|
|
|
func (h Handler) provisionUpstream(upstream *Upstream) {
|
|
// create or get the host representation for this upstream
|
|
upstream.fillHost()
|
|
|
|
// give it the circuit breaker, if any
|
|
upstream.cb = h.CB
|
|
|
|
// if the passive health checker has a non-zero UnhealthyRequestCount
|
|
// but the upstream has no MaxRequests set (they are the same thing,
|
|
// but the passive health checker is a default value for for upstreams
|
|
// without MaxRequests), copy the value into this upstream, since the
|
|
// value in the upstream (MaxRequests) is what is used during
|
|
// availability checks
|
|
if h.HealthChecks != nil && h.HealthChecks.Passive != nil {
|
|
h.HealthChecks.Passive.logger = h.logger.Named("health_checker.passive")
|
|
if h.HealthChecks.Passive.UnhealthyRequestCount > 0 &&
|
|
upstream.MaxRequests == 0 {
|
|
upstream.MaxRequests = h.HealthChecks.Passive.UnhealthyRequestCount
|
|
}
|
|
}
|
|
|
|
// upstreams need independent access to the passive
|
|
// health check policy because passive health checks
|
|
// run without access to h.
|
|
if h.HealthChecks != nil {
|
|
upstream.healthCheckPolicy = h.HealthChecks.Passive
|
|
}
|
|
}
|
|
|
|
// bufferedBody reads originalBody into a buffer, then returns a reader for the buffer.
|
|
// Always close the return value when done with it, just like if it was the original body!
|
|
func (h Handler) bufferedBody(originalBody io.ReadCloser) io.ReadCloser {
|
|
buf := bufPool.Get().(*bytes.Buffer)
|
|
buf.Reset()
|
|
if h.MaxBufferSize > 0 {
|
|
n, err := io.CopyN(buf, originalBody, h.MaxBufferSize)
|
|
if err != nil || n == h.MaxBufferSize {
|
|
return bodyReadCloser{
|
|
Reader: io.MultiReader(buf, originalBody),
|
|
buf: buf,
|
|
body: originalBody,
|
|
}
|
|
}
|
|
} else {
|
|
_, _ = io.Copy(buf, originalBody)
|
|
}
|
|
originalBody.Close() // no point in keeping it open
|
|
return bodyReadCloser{
|
|
Reader: buf,
|
|
buf: buf,
|
|
}
|
|
}
|
|
|
|
// cloneRequest makes a semi-deep clone of origReq.
|
|
//
|
|
// Most of this code is borrowed from the Go stdlib reverse proxy,
|
|
// but we make a shallow-ish clone the request (deep clone only
|
|
// the headers and URL) so we can avoid manipulating the original
|
|
// request when using it to proxy upstream. This prevents request
|
|
// corruption and data races.
|
|
func cloneRequest(origReq *http.Request) *http.Request {
|
|
req := new(http.Request)
|
|
*req = *origReq
|
|
if origReq.URL != nil {
|
|
newURL := new(url.URL)
|
|
*newURL = *origReq.URL
|
|
if origReq.URL.User != nil {
|
|
newURL.User = new(url.Userinfo)
|
|
*newURL.User = *origReq.URL.User
|
|
}
|
|
// sanitize the request URL; we expect it to not contain the
|
|
// scheme and host since those should be determined by r.TLS
|
|
// and r.Host respectively, but some clients may include it
|
|
// in the request-line, which is technically valid in HTTP,
|
|
// but breaks reverseproxy behaviour, overriding how the
|
|
// dialer will behave. See #4237 for context.
|
|
newURL.Scheme = ""
|
|
newURL.Host = ""
|
|
req.URL = newURL
|
|
}
|
|
if origReq.Header != nil {
|
|
req.Header = origReq.Header.Clone()
|
|
}
|
|
if origReq.Trailer != nil {
|
|
req.Trailer = origReq.Trailer.Clone()
|
|
}
|
|
return req
|
|
}
|
|
|
|
func copyHeader(dst, src http.Header) {
|
|
for k, vv := range src {
|
|
for _, v := range vv {
|
|
dst.Add(k, v)
|
|
}
|
|
}
|
|
}
|
|
|
|
// allHeaderValues gets all values for a given header field,
|
|
// joined by a comma and space if more than one is set. If the
|
|
// header field is nil, then the omit is true, meaning some
|
|
// earlier logic in the server wanted to prevent this header from
|
|
// getting written at all. If the header is empty, then ok is
|
|
// false. Callers should still check that the value is not empty
|
|
// (the header field may be set but have an empty value).
|
|
func allHeaderValues(h http.Header, field string) (value string, ok bool, omit bool) {
|
|
values, ok := h[http.CanonicalHeaderKey(field)]
|
|
if ok && values == nil {
|
|
return "", true, true
|
|
}
|
|
if len(values) == 0 {
|
|
return "", false, false
|
|
}
|
|
return strings.Join(values, ", "), true, false
|
|
}
|
|
|
|
// lastHeaderValue gets the last value for a given header field
|
|
// if more than one is set. If the header field is nil, then
|
|
// the omit is true, meaning some earlier logic in the server
|
|
// wanted to prevent this header from getting written at all.
|
|
// If the header is empty, then ok is false. Callers should
|
|
// still check that the value is not empty (the header field
|
|
// may be set but have an empty value).
|
|
func lastHeaderValue(h http.Header, field string) (value string, ok bool, omit bool) {
|
|
values, ok := h[http.CanonicalHeaderKey(field)]
|
|
if ok && values == nil {
|
|
return "", true, true
|
|
}
|
|
if len(values) == 0 {
|
|
return "", false, false
|
|
}
|
|
return values[len(values)-1], true, false
|
|
}
|
|
|
|
func upgradeType(h http.Header) string {
|
|
if !httpguts.HeaderValuesContainsToken(h["Connection"], "Upgrade") {
|
|
return ""
|
|
}
|
|
return strings.ToLower(h.Get("Upgrade"))
|
|
}
|
|
|
|
// removeConnectionHeaders removes hop-by-hop headers listed in the "Connection" header of h.
|
|
// See RFC 7230, section 6.1
|
|
func removeConnectionHeaders(h http.Header) {
|
|
for _, f := range h["Connection"] {
|
|
for _, sf := range strings.Split(f, ",") {
|
|
if sf = textproto.TrimString(sf); sf != "" {
|
|
h.Del(sf)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// statusError returns an error value that has a status code.
|
|
func statusError(err error) error {
|
|
// errors proxying usually mean there is a problem with the upstream(s)
|
|
statusCode := http.StatusBadGateway
|
|
|
|
// timeout errors have a standard status code (see issue #4823)
|
|
if err, ok := err.(net.Error); ok && err.Timeout() {
|
|
statusCode = http.StatusGatewayTimeout
|
|
}
|
|
|
|
// if the client canceled the request (usually this means they closed
|
|
// the connection, so they won't see any response), we can report it
|
|
// as a client error (4xx) and not a server error (5xx); unfortunately
|
|
// the Go standard library, at least at time of writing in late 2020,
|
|
// obnoxiously wraps the exported, standard context.Canceled error with
|
|
// an unexported garbage value that we have to do a substring check for:
|
|
// https://github.com/golang/go/blob/6965b01ea248cabb70c3749fd218b36089a21efb/src/net/net.go#L416-L430
|
|
if errors.Is(err, context.Canceled) || strings.Contains(err.Error(), "operation was canceled") {
|
|
// regrettably, there is no standard error code for "client closed connection", but
|
|
// for historical reasons we can use a code that a lot of people are already using;
|
|
// using 5xx is problematic for users; see #3748
|
|
statusCode = 499
|
|
}
|
|
return caddyhttp.Error(statusCode, err)
|
|
}
|
|
|
|
// LoadBalancing has parameters related to load balancing.
|
|
type LoadBalancing struct {
|
|
// A selection policy is how to choose an available backend.
|
|
// The default policy is random selection.
|
|
SelectionPolicyRaw json.RawMessage `json:"selection_policy,omitempty" caddy:"namespace=http.reverse_proxy.selection_policies inline_key=policy"`
|
|
|
|
// How many times to retry selecting available backends for each
|
|
// request if the next available host is down. If try_duration is
|
|
// also configured, then retries may stop early if the duration
|
|
// is reached. By default, retries are disabled (zero).
|
|
Retries int `json:"retries,omitempty"`
|
|
|
|
// How long to try selecting available backends for each request
|
|
// if the next available host is down. Clients will wait for up
|
|
// to this long while the load balancer tries to find an available
|
|
// upstream host. If retries is also configured, tries may stop
|
|
// early if the maximum retries is reached. By default, retries
|
|
// are disabled (zero duration).
|
|
TryDuration caddy.Duration `json:"try_duration,omitempty"`
|
|
|
|
// How long to wait between selecting the next host from the pool.
|
|
// Default is 250ms if try_duration is enabled, otherwise zero. Only
|
|
// relevant when a request to an upstream host fails. Be aware that
|
|
// setting this to 0 with a non-zero try_duration can cause the CPU
|
|
// to spin if all backends are down and latency is very low.
|
|
TryInterval caddy.Duration `json:"try_interval,omitempty"`
|
|
|
|
// A list of matcher sets that restricts with which requests retries are
|
|
// allowed. A request must match any of the given matcher sets in order
|
|
// to be retried if the connection to the upstream succeeded but the
|
|
// subsequent round-trip failed. If the connection to the upstream failed,
|
|
// a retry is always allowed. If unspecified, only GET requests will be
|
|
// allowed to be retried. Note that a retry is done with the next available
|
|
// host according to the load balancing policy.
|
|
RetryMatchRaw caddyhttp.RawMatcherSets `json:"retry_match,omitempty" caddy:"namespace=http.matchers"`
|
|
|
|
SelectionPolicy Selector `json:"-"`
|
|
RetryMatch caddyhttp.MatcherSets `json:"-"`
|
|
}
|
|
|
|
// Selector selects an available upstream from the pool.
|
|
type Selector interface {
|
|
Select(UpstreamPool, *http.Request, http.ResponseWriter) *Upstream
|
|
}
|
|
|
|
// UpstreamSource gets the list of upstreams that can be used when
|
|
// proxying a request. Returned upstreams will be load balanced and
|
|
// health-checked. This should be a very fast function -- instant
|
|
// if possible -- and the return value must be as stable as possible.
|
|
// In other words, the list of upstreams should ideally not change much
|
|
// across successive calls. If the list of upstreams changes or the
|
|
// ordering is not stable, load balancing will suffer. This function
|
|
// may be called during each retry, multiple times per request, and as
|
|
// such, needs to be instantaneous. The returned slice will not be
|
|
// modified.
|
|
type UpstreamSource interface {
|
|
GetUpstreams(*http.Request) ([]*Upstream, error)
|
|
}
|
|
|
|
// Hop-by-hop headers. These are removed when sent to the backend.
|
|
// As of RFC 7230, hop-by-hop headers are required to appear in the
|
|
// Connection header field. These are the headers defined by the
|
|
// obsoleted RFC 2616 (section 13.5.1) and are used for backward
|
|
// compatibility.
|
|
var hopHeaders = []string{
|
|
"Alt-Svc",
|
|
"Connection",
|
|
"Proxy-Connection", // non-standard but still sent by libcurl and rejected by e.g. google
|
|
"Keep-Alive",
|
|
"Proxy-Authenticate",
|
|
"Proxy-Authorization",
|
|
"Te", // canonicalized version of "TE"
|
|
"Trailer", // not Trailers per URL above; https://www.rfc-editor.org/errata_search.php?eid=4522
|
|
"Transfer-Encoding",
|
|
"Upgrade",
|
|
}
|
|
|
|
// DialError is an error that specifically occurs
|
|
// in a call to Dial or DialContext.
|
|
type DialError struct{ error }
|
|
|
|
// TLSTransport is implemented by transports
|
|
// that are capable of using TLS.
|
|
type TLSTransport interface {
|
|
// TLSEnabled returns true if the transport
|
|
// has TLS enabled, false otherwise.
|
|
TLSEnabled() bool
|
|
|
|
// EnableTLS enables TLS within the transport
|
|
// if it is not already, using the provided
|
|
// value as a basis for the TLS config.
|
|
EnableTLS(base *TLSConfig) error
|
|
}
|
|
|
|
// roundtripSucceeded is an error type that is returned if the
|
|
// roundtrip succeeded, but an error occurred after-the-fact.
|
|
type roundtripSucceeded struct{ error }
|
|
|
|
// bodyReadCloser is a reader that, upon closing, will return
|
|
// its buffer to the pool and close the underlying body reader.
|
|
type bodyReadCloser struct {
|
|
io.Reader
|
|
buf *bytes.Buffer
|
|
body io.ReadCloser
|
|
}
|
|
|
|
func (brc bodyReadCloser) Close() error {
|
|
bufPool.Put(brc.buf)
|
|
if brc.body != nil {
|
|
return brc.body.Close()
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// bufPool is used for buffering requests and responses.
|
|
var bufPool = sync.Pool{
|
|
New: func() any {
|
|
return new(bytes.Buffer)
|
|
},
|
|
}
|
|
|
|
// handleResponseContext carries some contextual information about the
|
|
// current proxy handling.
|
|
type handleResponseContext struct {
|
|
// handler is the active proxy handler instance, so that
|
|
// routes like copy_response may inherit some config
|
|
// options and have access to handler methods.
|
|
handler *Handler
|
|
|
|
// response is the actual response received from the proxy
|
|
// roundtrip, to potentially be copied if a copy_response
|
|
// handler is in the handle_response routes.
|
|
response *http.Response
|
|
|
|
// start is the time just before the proxy roundtrip was
|
|
// performed, used for logging.
|
|
start time.Time
|
|
|
|
// logger is the prepared logger which is used to write logs
|
|
// with the request, duration, and selected upstream attached.
|
|
logger *zap.Logger
|
|
|
|
// isFinalized is whether the response has been finalized,
|
|
// i.e. copied and closed, to make sure that it doesn't
|
|
// happen twice.
|
|
isFinalized bool
|
|
}
|
|
|
|
// ignoreClientGoneContext is a special context.Context type
|
|
// intended for use when doing a RoundTrip where you don't
|
|
// want a client disconnection to cancel the request during
|
|
// the roundtrip. Set its done field to a Done() channel
|
|
// of a context that doesn't get canceled when the client
|
|
// disconnects, such as caddy.Context.Done() instead.
|
|
type ignoreClientGoneContext struct {
|
|
context.Context
|
|
done <-chan struct{}
|
|
}
|
|
|
|
func (c ignoreClientGoneContext) Done() <-chan struct{} { return c.done }
|
|
|
|
// proxyHandleResponseContextCtxKey is the context key for the active proxy handler
|
|
// so that handle_response routes can inherit some config options
|
|
// from the proxy handler.
|
|
const proxyHandleResponseContextCtxKey caddy.CtxKey = "reverse_proxy_handle_response_context"
|
|
|
|
// Interface guards
|
|
var (
|
|
_ caddy.Provisioner = (*Handler)(nil)
|
|
_ caddy.CleanerUpper = (*Handler)(nil)
|
|
_ caddyhttp.MiddlewareHandler = (*Handler)(nil)
|
|
)
|